Devices for dispensing water treatment chemicals into swimming pools are known in the prior art. Many of these devices include a cylindrical housing for containing a single stack of dissolvable tablets of, for example, calcium hypochlorite. The upper end of the housing is circumscribed by a buoyant material so that the device floats in an upright orientation with its upper end above the water line when placed in a pool. One or more openings are provided at the lower end of the housing to allow ambient water to enter the housing, dissolve the tablets, and provide a stream of halogen solution that disinfects and otherwise treats the ambient water.
In operation, the size, number or path length of water-admitting openings in the housing of such dispensers is first adjusted to a size commensurate with the size of the pool or other body of water to be treated. Next, the solid, dissolvable water treating tablets are stacked or otherwise placed into the interior of the housing. Finally, the device is placed in the body of water. Ambient water circulates through the opening or openings in the lower end of the housing and dispenses a halogen solution at a rate consistent with the size of the pool or other body of water until all of the water treating chemical has dissolved.
While such devices have proven to be generally satisfactory for their intended purpose, the applicants have observed a number of areas in which improvement is desirable. For example, many of these floating devices provide no indication when a refill of water treatment chemical is due, which can result in a substantial hiatus in the treatment of the water. While one floating chemical dispenser is known wherein the buoyant housing lists over to one side when all of the water treatment chemical has dissolved, the visual signal is provided in an inelegant way which compromises the aesthetics of the device. While a skimmer-basket type chemical dispenser is known which includes a buoyant plate within a cylindrical container that floats to the top when all of the chemical is dissolved, the resulting visual signal (i.e. the portion of the plate visible through a top-mounted dispenser opening) is visible only within a narrow, vertical cone circumscribing a central axis of the cylindrical container. Hence such a signaling mechanism would be ineffective in a floating dispenser located in a central portion of the pool, as the signal generated would be difficult if not impossible to see from a side angle. Additionally, in all known prior art devices, no signal is generated until substantially all of the chemical has dissolved, thereby providing no “lead time” for refilling, which often results in a hiatus in the dispensing of the water treatment chemical.
Clearly, what is needed is a floating dispenser for dispensing water treatment chemicals that provides a visual indication that a refill of chemical is needed before all of the chemical has been dissolved. Ideally, the signal generated can be easily seen from all angles around the perimeter of the pool or other body of water. It would be desirable if the signal did not compromise the aesthetics of the device in the water. Finally, the dispenser should be easy to use and simple and inexpensive to manufacture.